A conventional high pressure spray-cleaning gun is as illustrated in FIG. 6, in which a cleaning solution receiver 92 is connected to the lower portion of a T junction 91, one end of the T junction 91 is connected to a nozzle 93, and the other end of the T junction 91 is connected to a handle 94. Compressed gas is controlled by the handle 94 and inputted through the T junction 91 to produce a Venturi tube effect, so that the cleaning solution in the cleaning solution receiver 92 can be pumped out and mixed by the nozzle 93 to form foam, which is then sprayed out.
However, a piece of foam 95 is mounted within the conventional nozzle 93, such that when the cleaning solution passes through the foam 95, it can be split or cleaved and then converted into foam. Nonetheless, according to the nozzle 93 of such structural design, when the cleaning solution enters the nozzle 93, it will directly enter the foam 95. Due to the influence of the specific gravity of the cleaning solution and the variation in the gas pressure, the cleaning solution entering the foam 95 cannot be effectively mixed, so that the amount of foam generated is clearly insufficient and thus the cleaning effect is significantly reduced. Furthermore, the nozzle opening 96 of the conventional nozzle structure 93 is a straight through hole, so the foam jetted therefrom is in a long column shape . When the surface area of an article to be cleaned is larger, it takes longer spraying time to complete a spraying operation for an entire large area. Therefore, it is more time-consuming and inconvenient.